(1) Field of the Invention
This invention relates to a fuel control system for a gasoline engine which enables both choking and throttling to be effected by remote control through a common operating mechanism.
(2) Description of the Prior Art
In gasoline engines suitable for use with lawn mowers, for example, of the prior art, it has hitherto been customary to use separate mechanisms for effecting choking and throttling, and this has made choking and throttling operations troublesome to perform. Moreover, when an attempt is made to rely on remote control to eliminate the need to manually handle the mechanisms in the vicinity of the engine in the interest of increased safety of operation, two systems of remote control mechanism are required, so that the fuel control system becomes complex in construction and difficulties are faced with in putting in to practical use.
To obviate the aforesaid disadvantages of the fuel control system of the prior art, proposals have been made to use a fuel control system of an intergrated type which enables choking and throttling operations to be performed in conjunction with each other, as described in Japanese Utility Model Laid-Open No. 26629/82, for example. In the integrated fuel control system of the prior art referred to hereinabove, an idling position and a choking position are set at opposite ends of the range of movement of an operating mechanism and a full-open throttle position is set midway between the idling position and the choking position. Thus, when a normal operation of the engine is performed by bringing a throttle valve to a full-open position, the operating mechanism might inadvertently be held in a position which is displaced from the full-open throttle position toward the choking position. When this happened, engine operation would continue while a choke valve is partly closed, thereby increasing fuel consumption. Also, the integrated fuel control system of the prior art has suffered the disadvantage that since the throttle valve is in the full-open position when the operating mechanism is in the choking position, the throttle valve would be temporarily brought to a full-open position and the number of revolutions of the engine would suddenly rise immediately after engines startup is effected by using the choke valve or when the operating mechanism is returned to the idling position. Moreover, an attempt to use common specifications for both the fuel control system of the integrated type and that of the separation type of the prior art to reduce production cost would fall through because of the need to effect changes on a large scale in the governor spring and other parts in the case of an engine equipped with a governor.